In many westernised countries including the United Kingdom and the United States of America, cardiovascular disease is a major cause of death. Public health campaigns supported by governments are being actively promoted in order to try to reduce mortality and morbidity from this cause. In almost all national dietary guidelines a prime recommendation is to reduce tonal dietary fat intake and in many a reduction in saturated fat is particularly stressed. In countries with a well-developed dairy industry, dairy products constitute a significant portion of the fat in the average diet, and because saturated fatty acids constitute about 60% of the total fatty acids in milk fat, dairy products account for an even larger proportion of the saturated fat consumed. For example, in the UK dairy products constitute 29% of the total fat in the average diet and 42% of the dietary saturated fatty acids.
Such has been the acceptance of the consensus view of the role of dietary saturated fatty acids in the aetiology of cardiovascular disease that, irrespective of the validity of the scientific evidence for those views, the dairy industry in those countries has come under pressure. In many such countries, liquid milk and butter sales have fallen steadily and the proportion of milk sales represented by low fat milks has increased dramatically.
Numerous clinical trials have shown that when a saturated fat diet is replaced by an unsaturated fat diet there is generally a fall in total serum cholesterol levels. It is widely conceded that dietary saturated fats cause an increase in cholesterol biosynthesis resulting in an increase in serum cholesterol levels regardless of the cholesterol content of the diet.
Polyunsaturated fats in the diet generally result in a lowering of both low-density lipoprotein cholesterol as well as high-density lipoprotein cholesterol. Monounsaturated fats on the other hand selectively lower the harmful low-density lipoprotein cholesterol (LDL) without altering the high-density lipoprotein cholesterol which, because of its ability to mobilize the LDL serum cholesterol so that it can be removed by the liver, is considered to be healthy.
With these nutritional problems in mind, a number of attempts have been made to replace the cholesterol-containing saturated fats in dairy products, particularly liquid milks, with polyunsaturated, cholesterol-free, vegetable oils and fats. Such milks are known generically as filled milks.
Natural milk comprises an emulsion of saturated fats in water. The emulsion is stabilised by the milk fat globule membrane, this membrane consists of a complex mixture of proteins, phospholipids, glycoproteins, triglycerides, cholesterol, enzymes and other minor components and acts as a natural emulsifying agent enabling the fat to remain dispersed throughout the aqueous phase of the milk. The filled milks previously proposed have utilised known emulsifying agents to maintain the polyunsaturated fats and oils in an emulsified state in the milk from which the natural saturated fats have been removed i.e. skim milk.
When the saturated milk fats are removed from whole milk the organoleptic properties of the remaining "skim milk" such as mouth-feel, flavor etc. are unacceptable to most consumers of liquid milk and milk products derived therefrom. It is not possible to simply recombine this skim milk with other non-dairy fats such as vegetable oils etc., without developing poor mouth-feel, off-flavors etc.
The present invention is directed to an alternative to such known filled dairy products and to premix preparations for use in producing dairy products according to this invention.